Generally, the ice used in seafood refrigeration industries are made from 100% fresh water or 100% sea water.
Small and medium sized fishing vessels are provided with the ice from the ice storage on the land, and some are supplied with the ice from an ice supply line at sea. In this case, it takes a lot of cost to maintain the freshness of the fish caught due to receiving the ice from the off-shore.
In addition, the freezing point of the ice with 100% fresh water is 0° C., but having a drawback that freshness is deteriorated due to osmotic phenomenon from the fish muscle. On the other hand, the frozen ice with 100% of seawater is excellent in precooling, but it is required a special facility to produce the ice using seawater.
The ice currently used for cooling of seafood preservation such as ice cube or sherbet ice contain a large amount of moisture and it causes swelling or deterioration of fish. Moreover, due to the size and the shape of ice itself, the contact area of the ice to the seafood is not even, resulting in local temperature variation at each point of contact. More specifically, when the ice is in contact with a fish, the muscle of the fish is damaged due to the temperature is too lower than desired preservation temperature because of the direct contact of the ice. On the other hand, the temperature of other area of fish where is not in direct contact with ice is not precisely controlled and sometimes above the desired temperature because the air is in the way and blocks the cool temperature dispersion from the ice to the fish. Thus the best outcome of seafood preservation is preferably achievable when using the fine particle ice type, more like powdered or snow shaped ice.
In addition, the one of the critical aspect of the powdered ice is to control the quality of water. The salinity in the water is maintained so that it contains same percentage of salt as sea water. When the powdered ice with same salinity as sea water is used in seafood preservation, its environmental condition is as closely same as in the sea, making the seafood is in more natural condition that minimize and slow down any deterioration process occurring in seafood when time elapses and prolongs the preservation period.
There was an artificial snow machine device as a coolant in U.S. Pat. No. 6,508,412 B1. But this prior art disclosed as a snow maker is normally used for creating snow for skiing and other recreational purpose. Also, this kind of snow maker did not control the size, quality of snow and its water source, which is considered as very important factors when using the powdered ice in seafood preservation industries. And the snow made from the artificial snow machine does not contain salinity.
In this regard, Korean Patent No. 10-0498735 disclosed a device for manufacturing seawater ice, but the ice maker according to the related art instantly crushed the ice after generating it, which disclosed the different apparatus and still producing coarse ice as an outcome.